TWO

The Universal Man

The intellectual climate of the Renaissance was decisively shaped by the philosophical and literary movement of humanism, which made the capabilities of the human individual its central concern. This was a fundamental shift from the medieval dogma of understanding human nature from a religious point of view. The Renaissance of fered a more secular outlook, with heightened focus on the individual human intellect. The new spirit of humanism expressed itself through a strong emphasis on classical studies, which exposed scholars and artists to a great diversity of Greek and Roman philosophical ideas that encouraged individual critical thought and prepared the ground for the gradual emergence of a rational, scientific frame of mind.

In Florence, the cradle of the Renaissance, the humanists’ enthusiastic embrace of discovery and learning gave rise to a new human ideal—l’uomo universale, the infinitely versatile “universal” man, educated in all branches of knowledge and capable of producing innovations in many of them. This ideal became so firmly associated with the Renaissance that later historians have commonly referred to it as the ideal of the “Renaissance man.” In the Florentine society of the fifteenth century, not only artists and philosophers but also merchants and statesmen strove to become “universal.” They became learned in Latin and Greek, conversant with the works of Aristotle, and familiar with classical treatises on natural history, geography, architecture, and engineering.¹

The Florentine humanists were inspired by several individuals in their midst who seemed to perfectly embody the ideal of the uomo universale. One of the first and most famous was Leon Battista Alberti, born half a century before Leonardo, to whom he seems the perfect precursor.² Alberti, like Leonardo, was said to be blessed with exceptional beauty and great physical strength, and he was also a skilled horseman and gifted musician. Moreover, he was a celebrated architect and accomplished painter, wrote beautiful Latin prose, studied both civil and canonical law as well as physics and mathematics, and was the author of several pioneering treatises on the visual arts. As a young man, Leonardo was fascinated by Alberti: He read him avidly, commented on his writings, and emulated him in his own life and work.

In his later years, Leonardo, of course, surpassed Alberti in both the breadth and depth of his work. The difference between Leonardo and the other “universal men” of the Italian Renaissance was not only that he went much farther than anyone else in his inquiries, asking questions nobody had asked before, but that he transcended the disciplinary boundaries of his time. He did so by recognizing patterns that interconnected forms and processes in different domains and by integrating his discoveries into a unified vision of the world.

Indeed, it seems that this is how Leonardo himself understood the meaning of universale. His famous statement, “Facile cosa è farsi universale”—“It is easy to become universal”—has often been interpreted to mean that infinite versatility was easy to acquire. When we read his assertion within the context in which it was made, however, an entirely different meaning becomes apparent. While discussing the proportions of the body, Leonardo wrote in his Treatise on Painting,

For a man who knows how, it is easy to become universal, since all land animals resemble each other in the parts of their body, that is, muscles, nerves, and bones, and differ only in length and size.³

For Leonardo, in other words, being universal meant to recognize similarities in living forms that interconnect different facets of nature—in this case, anatomical structures of different animals. The recognition that nature’s living forms exhibit such fundamental patterns was a key insight of the school of Romantic biology in the eighteenth century. These patterns were called Urtypen (“archetypes”) in Germany, and in England Charles Darwin acknowledged that this concept played a central role in his early conception of evolution.⁴ In the twentieth century, anthropologist and cyberneticist Gregory Bateson expressed the same idea in the succinct phrase “the pattern which connects.”⁵

Thus, Leonardo da Vinci was the first in a lineage of scientists who focused on the patterns interconnecting the basic structures and processes of living systems. Today, this approach to science is called “systemic thinking.” This, in my eyes, is the essence of what Leonardo meant by farsi universale. Freely translating his statement into modern scientific language, I would rephrase it this way: “For someone who can perceive interconnecting patterns, it is easy to be a systemic thinker.”

LEONARDO’S SYNTHESIS

Leonardo’s synthesis of art and science becomes easier to grasp when we realize that in his time, these terms were not used in the sense in which we understand them today. To his contemporaries, arte meant skill (in the sense we still use today when we speak of “the art of medicine,” or “the art of management”), while scientia meant knowledge, or theory. Leonardo insisted again and again that the “art,” or skill, of painting must be supported by the painter’s “science,” or sound knowledge of living forms, by his intellectual understanding of their intrinsic nature and underlying principles.

He also emphasized that this understanding was a continual intellectual process—discorso mentale—and that painting itself, therefore, deserved to be considered an intellectual endeavor.⁶ “The scientific and true principles of painting,” he wrote in the Trattato,” are understood by the mind alone without manual operations. This is the theory of painting, which resides in the mind that conceives it.”⁷ This conception of painting sets Leonardo apart from other Renaissance theorists. He saw it as his mission to elevate his art from the rank of a mere craft to an intellectual discipline on a par with the seven traditional liberal arts. (In the Middle Ages, the seven branches of learning known as the liberal arts were the “trivium” of grammar, logic, and rhetoric, whose study led to the Bachelor of Arts degree, plus the “quadrivium” of arithmetic, geometry, astronomy, and music, which led to the Master of Arts.)

The third element in Leonardo’s synthesis, in addition to arte (skill) and scientia (knowledge), is fantasia, the artist’s creative imagination. In the Renaissance, confidence in the capabilities of the human individual had become so strong that a new conception of the artist as creator had emerged. Indeed, the Italian humanists were so bold as to compare artistic creations to the creations of God. This comparison was first applied to the creativity of poets, and was then extended, especially by Leonardo, to the painter’s creative power:

If the painter wants to see beauties that make him fall in love, he is the lord who can generate them, and if he wants to see monstrous things that frighten, or funny things that make him laugh, or things that truly arouse compassion, he is their lord and God…. In fact, whatever there is in the universe, by essence, presence, or imagination, he has it first in his mind and then in his hands.⁸

For Leonardo, the artist’s imagination always remains closely linked to his intellectual understanding of nature. “The inventions of his fantasia,” explains Martin Kemp, “are never out of harmony with universal dynamics as rationally comprehended; they are fabulous yet not implausible, each element in their composition deriving from the causes and effects of the natural world.”⁹ At the same time, Leonardo insisted on the divine quality of the painter’s creativity. “The godlike nature of the science of painting,” he declared, “transforms the painter’s mind into a resemblance of the divine mind.”¹⁰

Leonardo realized that fantasia is not limited to artists, but rather is a general quality of the human mind. He called all human creations—artifacts as well as works of art—“inventions,” and he made an interesting distinction between human inventions and the living forms created by nature. “Nature encompasses only the production of simple things,” he argued, “but man from these simple things produces an infinity of compounds.”¹¹

From the modern scientific perspective, this distinction no longer holds, because we know that in the process of evolution, nature, too, produces living forms through an infinity of new compounds from cells and molecules. However, in a broader sense, Leonardo’s distinction is still valid as a distinction between forms that emerge through evolution and forms created by human design. In contemporary scientific language, Leonardo’s term “simple things” would be replaced by “emergent structures” and his notion of “compounds” by “designed structures.”¹²

Throughout his life, Leonardo referred to himself as an inventor. In his view, an inventor was someone who created an artifact or work of art by assembling various elements into a new configuration that did not appear in nature. This definition comes very close to our notion of a designer, which did not exist in the Renaissance. (Leonardo’s term disegnatore, sometimes incorrectly translated as “designer,” always means “draftsman” a better equivalent of “designer” is his term compositore.) The concept of design as a distinct profession emerged only in the twentieth century as a consequence of mass production and industrial capitalism.¹³ During the preindustrial era, design was always an integral part of a larger process that included problem solving, innovation, form giving, decoration, and manufacturing. This process traditionally took place in the domains of engineering, architecture, crafts, and the fine arts.

Accordingly, Leonardo did not separate the design process—the abstract configuration of multiple elements—from the process of material production. However, he always seemed to be more interested in the process of design than in its physical realization. It is worthwhile to recall that most of the machines and mechanical devices he invented, designed, and presented in superb drawings were not built; most of his military inventions and schemes of civil engineering were not realized; and although he was famous as an architect, his name is not connected with any known building. Even as a painter he often seemed to be more interested in the solution of compositional problems—the discorso mentale—than in the actual completion of the painting.

It seems to me, then, that the wide-ranging activities and achievements of Leonardo da Vinci, the archetypal uomo universale, are best examined within the three categories of artist, designer, and scientist. In his own synthesis, the activities of the inventor, or designer, like those of the artist, are inextricably linked to scientia, the knowledge of natural principles. He referred to himself, in one of his most arresting expressions, as “inventor and interpreter between nature and humans.”¹⁴

THE SUBLIME LEFT HAND

In practice, it was Leonardo’s exceptional drawing facility that formed the link between the three domains of art, design, and science, as he himself recognized:

Drawing, [the foundation of painting], teaches the architect to render his building agreeable to the eye; this is what teaches potters, goldsmiths, weavers, embroiderers. It has found the characters by which different languages are expressed; it has given the arithmeticians their ciphers and has taught geometers how to represent their figures; it instructs the experts in perspective, astronomers, machine builders, and engineers.¹⁵

With his acute powers of observation and his “sublime left hand” (as his friend, the mathematician Luca Pacioli, called it), Leonardo was able to draw, in exquisite detail, flowers, birds in flight, whirlpools, muscles and bones, and human expressions with unparalleled accuracy (see Fig. 2-1). Writing about the studies for his early Madonnas, Kenneth Clark comments, “They show his matchless quickness of vision, which allowed him to convey every movement or gesture with the certainty and unconscious grace of a great dancer performing a familiar step.”¹⁶

Figure 2-1: Madonna and Child and other studies, c. 1478–80, Drawings and Miscellaneous Papers, Vol. III, folio 162r

Leonardo’s anatomical drawings were so radical in their conception that they remained unrivaled until the end of the eighteenth century, nearly three hundred years later. Indeed, they have been praised as the beginning of modern anatomical illustration.¹⁷ To present the knowledge he had gathered from his extensive anatomical dissections, Leonardo introduced numerous innovations: drawing structures from several perspectives; drawing in cross sections and “exploded” views; showing the removal of muscles in successive layers to expose the depths of an organ or anatomical feature. None of his predecessors or contemporaries came close to him in anatomical detail and accuracy.

To the few of his contemporaries who were privileged to see them, Leonardo’s anatomical manuscripts must have seemed almost miraculous. When the Cardinal of Aragon visited the old master in France in 1517, his secretary, Antonio de Beatis, wrote in his journal: “This gentleman has written a treatise on anatomy, showing the limbs, muscles, nerves, veins, joints, intestines, and everything that can be explained in the body of men and women, in a way that has never been done by anyone before.”¹⁸

Leonardo called his anatomical drawings “demonstrations,” adopting a terminology typically used by mathematicians to refer to their diagrams, and he proudly asserted that they gave “true knowledge of [various] shapes, which is impossible for either ancient or modern writers…without an immense, tedious and confused amount of writing and time.”¹⁹ Indeed, when looking through the Anatomical Studies, it is evident that Leonardo’s main focus is on the drawings. The accompanying text is secondary, and sometimes absent altogether. In a way, these manuscripts are reminiscent of modern scientific papers in which the main statements are the mathematical equations, with a few explanatory lines between them (see Fig. 2-2).

Leonardo used the same innovative techniques that he perfected in his anatomical drawings in his vast collection of technical drawings of mechanisms and machines. A multitude of mechanical elements in different combinations are presented in cutaway or exploded views and from many sides, with great mastery of visual perspective and subtle renderings of light and shade (see Fig. 2-3). Drawings of similar machines were produced by other Renaissance engineers. However, as art historian Daniel Arasse points out, while theirs are merely explanatory, Leonardo’s are convincing, persuading the viewer of the feasibility and soundness of the author’s designs:

Figure 2-2: Muscles of the arm and shoulder in rotated views, c. 1510, Anatomical Studies, folio 141v

Figure 2-3: Two-wheeled hoist, Codex Atlanticus, folio 30v

His working drawings not only possess a rare elegance; they are visually put in context, and they have the concrete appearance of objects which exist: the angle or angles of view, the subtlety of the shadows and the treatment of the background itself on which they are drawn gives them an extraordinarily persuasive…effectiveness.²⁰

As an artist, Leonardo introduced a novelty into the practice of preparatory drawing, which forms an intriguing counterpoint to the precision of his scientific and technical drawings.²¹ In many studies for his paintings, he would go over the outlines of a figure again and again, sketching several alternative lines and variations of the figure’s position, until he found the ideal form. These preparatory sketches have an extraordinary dynamic quality. One can almost feel the rhythm of Leonardo’s “sublime left hand” as he tries out different possibilities, translating his discorso mentale into a blur of lines. In Leonardo’s time, this technique was unprecedented, as Martin Kemp describes:

Never before had any artist worked out his compositions in such a welter of alternative lines. The pattern-book drawing techniques of the fourteenth and fifteenth centuries, which Verrocchio had relaxed in some measure, have here been overthrown in a “brain storm” of dynamic sketching. Such flexibility of preparatory sketching became the norm for later centuries; it was introduced almost single-handedly by Leonardo.²²

Sometimes—as, for example, in a study for his famous Madonna and Child with Saint Anne—Leonardo would push his technique of dynamic sketching to an extreme, producing what Arasse describes as “an unreadable blur. Nothing can any longer be distinguished in this chaos, but his eye has perceived in the movement of his hand the hidden, buried, latent form, straining to become a figure. Leonardo marks this with a stylus and, turning the sheet over, makes it visible with a distinct line.”²³

To me, this is a fascinating visual illustration of the process known to complexity theorists as “emergence”—the spontaneous emergence of new forms of order out of chaos and confusion.²⁴ According to complexity theory, creativity—the generation of new forms—is a key property of all life, and it involves the very process that Leonardo revealed in his exquisite preparatory drawings. I would argue that our most creative insights emerge from such states of uncertainty and confusion.

THE SOUL OF PAINTING

Although he kept his scientific ideas to himself, Leonardo freely shared his views on painting with his students and fellow artists. At his death he left over six hundred pages of detailed instructions for painters, covering all aspects of his science and art of painting. From this vast collection, scattered through eighteen of Leonardo’s Notebooks (over half of which, as noted earlier, are now lost), his friend and disciple Francesco Melzi compiled the famous anthology known as Trattato della pittura (Treatise on Painting).²⁵ First published in 1651, it was soon translated throughout Europe, and remained a standard text for art students for three centuries.

The first part of the Trattato, known as the “Paragone” (“Comparison”), is a long polemical “debate” comparing painting to poetry, music, and sculpture.²⁶ This kind of polemic was fashionable in the fifteenth century, and Leonardo’s highly original arguments in favor of painting are so lively and witty that we can easily imagine him presenting them in an actual debate.

“Painting serves a more noble sense than poetry,” he argues, “and renders the figures of the works of nature with more truth than the poet does.” He continues in a lighter vein: “Take a poet who describes the beauties of a lady to her lover, and take a painter who represents her, and you will see where nature will turn the enamored judge.”²⁷ Music ought to be called “the younger sister of painting,” Leonardo suggests, “since it composes harmony from the conjunctions of its proportional parts…. Yet painting excels and rules over music, because it does not immediately die after its creation the way the unfortunate music does.”²⁸ What about sculpture? Surely, no painting endures as well as marble or bronze? True, he admits, “sculpture has the greatest resistance to time.” Nevertheless, painting is far superior, because sculpture “will not produce lucid and transparent bodies like the veiled figures that show the nude flesh under the veils laid against it. It will not produce the minute pebbles of varied colors below the surface of transparent waters.” Sculptors, he continues, “cannot represent…mirrors and similar lustrous things, nor mists, nor bad weather, nor infinite other things that I need not mention because it would be too tedious.”²⁹

The deeper purpose of Leonardo’s lively polemic was to advance persuasive arguments for considering painting as a mental activity and a science, far above the rank of a mere craft. At the beginning of the Renaissance, painting was classified as a “mechanical art,” together with crafts like gold and metal work, jewelry, tapestry, and embroidery. None of these mechanical arts stood out in terms of prestige, and their practitioners remained relatively anonymous. Commissions would typically specify the quality of the raw materials (gold leaf, lapis lazuli, etc.), which was more important to the patron than the name of the artist.³⁰

When Florence became a major artistic center in the fourteenth century, its painters began to share their knowledge and experience, and collectively developed many technical innovations. They perfected the fresco technique (the art of painting al fresco, that is, on freshly spread moist plaster), introduced panel painting, and, a century later, pioneered perspective and oil painting. The Florentine painters and sculptors also established an elaborate apprenticeship system, with strict quality control under the supervision of professional guilds, all of which enhanced their prestige and gradually elevated their professions above the anonymous world of craftsmen.

Leonardo committed himself to advancing this process of emancipation, to convince society that painting should be considered an intellectual enterprise, a true liberal art. To distinguish painting from manual labor, Alberti, in his 1435 book De Pictura (On Painting), had already discussed the importance of mathematics, one of the liberal arts of the time, as the foundation of perspective and the geometry of shadows, and by implication as the intellectual core of painting as a whole.³¹ Leonardo followed in Alberti’s footsteps but then went beyond him by promoting painting as an intellectual discipline based not only on mathematics but on the theoretical knowledge of “all the qualities of forms.”³²

As a painter, Leonardo excelled especially in modeling subtle gradations of light and dark, known to art historians as chiaroscuro. He revolutionized painting by completely reconceptualizing traditional techniques. “In his use of light and shade, Leonardo was the precursor of all subsequent European painting,” writes Kenneth Clark.”³³

The essence of Leonardo’s innovation lies in his use of shadow as a unifying element, a theme that brings out different qualities of tone and color. As Martin Kemp explains in his discerning analysis of Leonardo’s Virgin of the Rocks,

From [the] soft substratum of velvety shadow emerge the colors, revealed only by the presence of light…. Within this unity of shadow an infinite subtle series of adjustments are made to accommodate the inherent tonal values of different colors, from the lightest yellow to the deepest of blues.³⁴

One of the hallmarks of a master painter in the Florentine tradition was the ability to represent figures in apparent three-dimensional relief. “The first task of the painter,” writes Leonardo, “is to make a flat surface appear as a body in relief, standing out from that surface, and he who surpasses the others in that skill deserves most praise.”³⁵ As Kenneth Clark explains, Leonardo was not content to achieve this effect by “the subtle combination of drawing and surface modeling which the painters of the quattrocento [fifteenth century] had brought to perfection. He wished to achieve relief through the scientific use of light and shade.”³⁶ According to Leonardo, such an achievement is “the soul of painting.”³⁷

Leonardo’s technique of using light and shade to give his figures “great vigor and relief,” as Vasari put it, culminated in his celebrated creation of sfumato, the subtle melting of shades that eventually became the unifying principle of his paintings. “Leonardo’ssfumato was the power behind the poetry of his paintings,” Arasse claimed, “and the mystery that seems to emanate from them.”³⁸

It is clear from Leonardo’s writings on the use of light and shade that he derived his knowledge from a series of systematic experiments with lamps shining on a variety of geometrical solids. He drew numerous complex diagrams showing the formation, projection, intersections, and gradations of shadows in endless combinations. As I will show later in the book, his detailed investigations of vision, the nature of light and shadow, and the appearance of forms were the gateway to his science of painting.³⁹

Leonardo’s earliest existing notes on shadow and light date from around 1490,⁴⁰ but it is evident from his Virgin of the Rocks (1483–86) that he had thoroughly mastered the basic concepts several years earlier. His power of observation, combined with his intuitive understanding of light, allowed him to render not only the most subtle gradations of chiaroscuro, but also complex secondary effects of light—reflected sheens, areas of diffused light, subtle glows, and the like—with unprecedented mastery. According to Kemp, “No one until the nineteenth century was to achieve a comparable level of intensity in depicting the elusive complexities of visual phenomena.”⁴¹

DISCORSO MENTALE

Leonardo could not have developed his mastery of chiaroscuro, nor his characteristic sfumato style, without a major advance in Renaissance painting—the use of oil-based paints. Oil painting makes it possible to put layers of paint on top of each other without blurring the colors (provided the layers are allowed to dry individually), to go back over work again and again, and to mix paints at ease, all of which were essential for Leonardo to achieve his special effects of relief and sfumato.

Oil painting is said to have been invented by the Flemish master Jan van Eyck. According to Vasari, the technique was introduced in Italy first in Naples, Urbino, and Venice before eventually reaching Florence, where it caused a sensation. When Leonardo was an apprentice in Verrocchio’s workshop, the Tuscan painters had not yet fully mastered the technique of oils. Leonardo became a major figure in its perfection, together with his fellow student Perugino, who passed their secrets on to Raphael.⁴²

Over the years, Leonardo achieved a sublime mastery in applying the finest layers of paint to create the luminous color tones that give his paintings their special magic. As Serge Bramly describes it, “The light passes through his paintings as if through stained glass, straight on to the primed surface beneath, which reflects it back, thus creating the impression that it emanates from the figures themselves.”⁴³

The slow and careful process of painting that is required by oils was ideal for Leonardo’s approach. He could spend weeks between layers of paint, and could rework and refine his panels for years, reflecting on every detail of their conception, engaging in the mental discourse that he saw as the essence of his art and science. This discorso mentale, the intellectual process of painting, was often more important to Leonardo than the actual completion of the work. Consequently, the total output of his life as a painter was relatively small, especially in view of the profound impact he had on the subsequent history of European art.

On the other hand, Leonardo’s completed masterpieces always involved radical innovations at several levels—artistic, philosophical, and scientific. For example, the Virgin of the Rocks (Fig. 2-4) was not only revolutionary in its rendering of light and dark. It also represented a complex and controversial meditation on the destiny of Christ, expressed through the gestures and relative positions of the four protagonists, as well as in the intricate symbolism of the surrounding rocks and vegetation.⁴⁴

Figure 2-4: Virgin of the Rocks, c. 1483–86, Musée du Louvre, Paris

The rocks themselves are rendered with astounding geological accuracy. Leonardo depicted a complex geological formation involving soft, weathered sandstone dissected by a layer of harder rock known to geologists as diabase. Numerous fine details in the rocks’ textures and weathering patterns show the artist’s profound knowledge, unmatched in his time, of such geological formations.⁴⁵ And finally—in a dramatic departure from the traditional decorative use of plants in the quattrocento—the plants growing in the surroundings of the rocky grotto are rendered not only in exquisite botanical detail but also in their proper habitat, with complete seasonal and ecological accuracy.⁴⁶

Observations of similar innovations can be made in The Last Supper, the Mona Lisa, or the Madonna and Child with Saint Anne. It is no wonder that each of these masterpieces caused great commotion among Leonardo’s contemporaries, generating animated discussions and numerous copies, which expanded the master’s discorso mentale throughout Europe’s artistic and intellectual circles.

IL CAVALLO

In the “Paragone,” Leonardo introduces one of his lengthy arguments about the superiority of painting over sculpture with the following self-assured words:

As I apply myself in sculpture no less than in painting, and practice both in the same degree, it seems to me that without being suspected of unfairness I can judge which of the two is of greater ingenuity and of greater difficulty and perfection.⁴⁷

In a similar vein, Vasari refers to Leonardo as “Florentine painter and sculptor” in the title of his biography. And yet, we have no known sculpture from Leonardo’s hand. His reputation as a sculptor rests on a single piece of work: a monumental bronze horse that was never cast, but which occupied Leonardo intensely for over ten years.

When he was in his late thirties and employed as “painter and engineer” at the court of Ludovico Sforza in Milan, Leonardo received a commission for an equestrian statue honoring the duke’s father. The city’s tremendous wealth at the time encouraged grandiose schemes, and accordingly Ludovico wanted the equestrian monument to be grandissimo, perhaps three or four times life-size. A bronze sculpture of that size had never been attempted before. The unprecedented challenges of the project fascinated Leonardo, and even though he was generally not fond of sculpture, he eagerly accepted the commission. It was a project that would draw on his scientific interests in anatomy, proportion, and the animal body in motion as well as his engineering skills and artistic talent. Beautifully told by Serge Bramly in his biography Leonardo: Discovering the Life of Leonardo da Vinci, the episode is closely linked to the fluctuating fortunes of the Sforza dynasty.⁴⁸

At first, Leonardo considered a horse rearing over a vanquished enemy. The forceful vitality of that image appealed to him, but the structural problems turned out to be forbidding even for his genius. How could he create a horse weighing many tons that could stand on two legs? Even if he created additional support by making one of the forelegs rest on the vanquished enemy, how could he cast and balance the entire group? After a long and careful examination of these staggering technical difficulties, Leonardo abandoned the idea of a rearing horse and eventually settled on the classical pose of an antique equestrian statue, known as the Regisole, which he had greatly admired in Pavia.⁴⁹ He had been especially impressed by the statue’s natural grace. “The movement is more praiseworthy than anything else,” he jotted down in his notebook. “The trot almost has the quality of a free horse.”⁵⁰

While he pondered various poses of the bronze horse and the associated engineering problems, Leonardo seemed to have completely forgotten its rider. The statue of Duke Francesco, clad in armor, was to be cast separately and added later, but over the years Leonardo became so absorbed by the physical beauty, proportions, and movements of the horse that he referred to the monument simply as il cavallo.

Once he settled on the final pose of the horse, Leonardo repeatedly visited the princely stables of Ludovico as well as those of other wealthy Milanese noblemen in search of models for his cavallo. He identified several superb thoroughbreds, measured them meticulously to determine their proportions, and drew them from life in numerous positions. In typical fashion, he got carried away with the intellectual aspects of the undertaking, expanded it into a major research project, and ended up with a full treatise on the anatomy of the horse.⁵¹ In addition, he produced a wealth of artistic studies of horses, now assembled in a special volume of the Royal Collection at Windsor Castle. In the opinion of art critic Martin Kemp, “No one has ever captured more convincingly the rippling beauty of a finely bred and groomed horse.”⁵²

Finally, after four years of preparatory studies, Leonardo built a full-scale model of the sculpture out of clay. At a height of slightly over twenty-three feet, it towered over the most famous equestrian statues of the time—that of Marcus Aurelius on the Capitol in Rome, Donatello’s Gattamelatain Padua, and Verrocchio’s Colleoni in Venice. Not surprisingly, the colossal model generated enormous excitement when it was displayed in front of the Sforza castle on the occasion of the marriage of Ludovico’s niece Bianca Maria to the emperor Maximilian. “The vehement, life-like action of this horse, as if panting, is amazing,” wrote Paolo Giovio, “not less so the sculptor’s skill and his consummate knowledge of nature.” Vasari claimed that those who saw the clay model felt that they had never seen a more magnificent piece of work. The court poets composed Latin epigrams in praise of the gran cavallo, and Leonardo’s fame as a sculptor soon spread throughout Italy.

While completing the model, Leonardo thought deeply about the tremendous challenge of casting such a large piece. He collected all his notes on the subject in seventeen folios of a book (now bound at the end of the Codex Madrid II), beginning with the words: “Here a record shall be kept of everything related to the bronze horse presently under construction.”⁵³

The traditional method of casting was to divide the work into several smaller pieces to be cast separately, but Leonardo concluded that it would not be possible to make all the pieces of uniform thickness. As a result, he would not be able to estimate their weight and establish in advance the overall balance of the sculpture. Having investigated all aspects of the problem with his usual attention to meticulous details, he decided to cast the horse in one piece, something that had never been attempted before. His voluminous notes have allowed art historians to reconstruct Leonardo’s method in detail.⁵⁴ It involved digging a huge pit to bury the mold upside down, so that the molten metal could run in through the animal’s belly while the air escaped upward through the feet.

Leonardo left very detailed and beautiful drawings of the iron framework he had designed for the horse’s head and neck, held in place by an ingenious set of hooks and wires. Other drawings show the wooden frame he intended to build for transporting the giant mold, as well as the elaborate machinery for maneuvering it. His descriptions cover every conceivable aspect of the casting process—from recipes for alloys and methods for controlling the temperature in the furnaces to dress rehearsals with small-scale models.

By early 1494, everything was ready for the casting. The materials had been acquired, and a start was probably made on digging the pit and building four specially designed furnaces around it. But then political necessity intervened. During the previous two years, several Italian political leaders had died, European alliances had shifted, and now Charles VIII, the new king of France, was about to attack Milan. Under this imminent threat, Ludovico decided to use Leonardo’s precious seventy-two tons of bronze for new cannon instead of the gran cavallo. Leonardo remained optimistic that he would be able to proceed eventually, and continued to work on his project. But Ludovico ran out of money. It became clear that the glorious monument would never be cast. About a year later, Leonardo attached a simple note to a letter he had written to the duke: “About the horse I will say nothing, for I know the times.”⁵⁵

Leonardo’s molds were never used, and his giant clay model eventually crumbled and decayed. His fame as a sculptor, however, lived on, as did his novel method of casting. Two hundred years later, it was used in France to make an enormous equestrian statue of Louis XIV, almost as tall as thegran cavallo. “Even the stance of the horse was the same,” Bramly tells us, “and by remarkable coincidence, the same bad luck attended the statue: it was destroyed during the Revolution, so we cannot see it. But the fact that it was cast at all shows that [Leonardo’s] method was sound.”⁵⁶

LEONARDO THE DESIGNER

Upon reflecting on the great diversity of Leonardo’s interests and pursuits, virtually all those that cannot be seen strictly as “art” or “science” may be subsumed under the broad category of “design.” The notion of design as a distinct discipline emerged only in the twentieth century: As a result, viewing Leonardo as a designer means applying a modern category that did not exist in his time.⁵⁷ Nevertheless, it seems intriguing to examine his wide-ranging pursuits from our contemporary perspective.

Design, then and now, has always been an integral part of a larger process of giving form to objects.⁵⁸ At its outset, the design process is purely conceptual, involving the visualization of images, the arrangement of elements into a pattern in response to specific needs, and the drawing of a series of sketches representing the designer’s ideas. All these are activities that fascinated Leonardo and in which he excelled.

As the design process matures and moves closer to the implementation phase, its dependence on other disciplines increases. Hence, we classify different types of design according to the domains in which they operate. Today’s design disciplines include those associated with civil, military, and mechanical engineering; architectural design; landscape and garden design; urban design; fashion and costume design; stage and theatrical design; and graphic design. Leonardo da Vinci was active in all these “design disciplines” throughout his life.

Good designers have the ability to think systemically and to synthesize. They excel at visualizing things, at organizing known elements into new configurations, at creating new relationships; and they are skillful in conveying these mental processes in the form of drawings almost as rapidly as they occur. Leonardo, of course, possessed all these abilities to a very high degree. In addition, he had an uncanny knack of perceiving and solving technical problems—another key characteristic of a good designer—so much so, in fact, that it was almost second nature to him.

Many of the machines and mechanical devices he drew were not original. But when he took them from sketches of earlier inventors, he would invariably modify and improve their design, often beyond recognition. When he worked on the large cartoon of The Battle of Anghiari, he constructed an ingenious scaffolding, according to Vasari, “which he could raise or lower by drawing it together or extending it.” While he spent long hours in the Sforza stables drawing thoroughbred horses from life, he also designed and sketched a model stable featuring automated supply lines of fodder and water as well as runoffs for liquid manure, which would provide the basis for the Medici stables twenty-five years later.⁵⁹ Whatever he was engaged in, technical innovations were never far from Leonardo’s mind.

FROM ENGINEERING TO SCIENCE

It was during his employment as “painter and engineer” at the Sforza court that Leonardo’s technical inventiveness came into full bloom. The duties of an artist at a Renaissance court included, besides painting portraits and designing pageants and festivities, a variety of small engineering jobs that demanded unusual ingenuity and skills in the handling of materials.⁶⁰ Leonardo’s many creative talents were perfectly suited for this. He invented a large number of astonishing devices during this time, which brought him considerable fame as an engineer-magician.

Many of these inventions were extraordinary for the period.⁶¹ Among them were doors that opened and closed automatically by means of counterweights; a table lamp with variable intensity; folding furniture; an octagonal mirror that generated an infinite number of multiple images; and an ingenious spit, in which “the roast will turn slow or fast, depending upon whether the fire is moderate or strong.”⁶² Other inventions of a more industrial nature included a press for making olive oil, and a variety of textile machines for spinning, weaving, twisting hemp, trimming felt, and making needles.⁶³ Leonardo remained an avid inventor throughout his life. The total number of inventions attributed to him has been estimated at three hundred.⁶⁴

But this combination of artist-engineer was not unusual in the Renaissance. Leonardo’s teacher Verrocchio, for example, was a renowned goldsmith, sculptor, and painter as well as a reputable engineer. The great Renaissance architect Brunelleschi was trained as a goldsmith and first gained notice in Florence as a sculptor. Later on, when he was famous as an architect, he was also acclaimed for his inventive genius as an engineer, both civil and military. Brunelleschi died six years before Leonardo was born. The young Leonardo admired him greatly and declared his indebtedness to the great architect by drawing several of Brunelleschi’s renowned lifting devices and architectural plans.⁶⁵

What made Leonardo unique as a designer and engineer, however, was that many of the novel designs he presented in his Notebooks involved technological advances that would not be realized until several centuries later.⁶⁶ And second, he was the only man among the famous Renaissance engineers who made the transition from engineering to science. Like painting, engineering became a “mental discourse” for him. To know how something worked was not enough for Leonardo; he also needed to know why. Thus an inevitable process was set in motion, which led him from technology and engineering to pure science. As art historian Kenneth Clark notes, we can see the process at work in Leonardo’s manuscripts:

First, there are questions about the construction of certain machines, then…questions about the first principles of dynamics; finally, questions which had never been asked before about winds, clouds, the age of the earth, generation, the human heart. Mere curiosity has become profound scientific research, independent of the technical interests which had preceded it.⁶⁷

ARCHITECTURAL DESIGN

Leonardo was active in the field of architecture throughout his life, but his name is not associated with any church or other building, nor is he mentioned in any architectural contract. Yet he was praised as an “excellent architect” by his contemporaries, and art historians such as Ludwig Heydenreich and Carlo Pedretti feel that he deserved this reputation.⁶⁸

In architecture, as in many other fields, Leonardo’s main interest was in design. His Notebooks are full of architectural drawings; he produced numerous designs for villas, palaces, and cathedrals, and he was often consulted as an expert on architectural problems.⁶⁹ However, his drawings are not of the kind that a patron would expect from a professional architect. They are never precise proposals or detailed plans, and, as Daniel Arasse observes, they are remarkably free of “any studies of the details of architectural vocabulary (columns, capitals, frames, cornices, moldings, and so on). It is the syntax, the logical linking and the reciprocal organization of the parts of the building that interest Leonardo.”⁷⁰

In other words, the problems Leonardo addresses are theoretical problems of architectural design. The questions he asks are the same questions he explores throughout his science of organic forms—questions about patterns, spatial organization, rhythm, and flow. The notes accompanying his drawings (written in his customary mirror writing, and hence intended for himself) can be seen as fragments of a treatise on architecture that Leonardo, according to Heydenreich, may have intended to compose.⁷¹

As a result of his unique systemic approach to architecture, Leonardo’s architectural design is characterized by a remarkable indifference to classical forms and a high degree of originality. “The solutions which he imagines,” writes Arasse, “are invariably (brilliantly) unconventional—that is to say, they are not ‘classical,’ being simultaneously Gothic in some respects and already Mannerist in others.”⁷²

Leonardo’s originality revealed itself in his seemingly effortless integration of architecture and complex geometry. This is especially apparent in his many designs of centralized, radially symmetric churches and “temples” (see Fig. 2-5). Although churches with such central plans were a favorite design of Alberti, Brunelleschi, and other Renaissance architects, the playful clusters of geometric patterns—almost reminiscent of the fractals of today’s complexity theory—are unique to Leonardo. “The mathematical integration of the parts,” observes Martin Kemp, “somehow achieves a compelling sense of organic unity in the exterior perspective of the building in a way which is uniquely his own. Equally impressive and characteristic is the spatial vision which allows him to display his design as a fully three-dimensional concept, like a piece of sculpture, rather than as a compound of plan and flat elevations.”⁷³

Figure 2-5: Design for Centralized “Temple,” c. 1488, Ms. Ashburnham I, folio 5v

In view of Leonardo’s central focus on understanding nature’s forms, both in the macro-and the microcosm, it is not surprising that he emphasized similarities between architectural structures and structures in nature, especially in human anatomy. In fact, this linking of architecture and anatomy goes back to antiquity and was common among Renaissance architects, who recognized the analogy between a good architect and a good doctor.⁷⁴ As Leonardo explained,

Doctors, teachers, and those who nurse the sick should understand what man is, what is life, what is health, and in what manner a parity and concordance of the elements maintains it, while a discordance of these elements ruins and destroys it…. Thesame is also needed for the ailing cathedral, that is, a doctor-architect who understands well what a building is and from what rules the correct way of building derives.⁷⁵

However, Leonardo went beyond the common analogies, for example, comparing the dome of a church to the human cranium, or the arches in its vaulting to the rib cage. Just as he was keenly interested in the body’s metabolic processes—the ebb and flow of respiration, and the transport of nutrients and waste products in the blood—he also paid special attention to the “metabolism” of a building, studying how stairs and doors facilitate movement through the building.⁷⁶ A sheet from the Windsor Collection showing a diagram of human blood vessels next to a series of sketches of stairs makes it clear that Leonardo consciously applied the metaphor of metabolic processes in his architectural designs.⁷⁷

Leonardo’s special attention to how movements would flow through his buildings was not restricted to the interiors, but included the surrounding grounds as well, by means of doorways, loggias, and balconies. In fact, in most of his designs of villas and palaces, he considered the garden to be an integral part of the house. These designs reflect his continual efforts to integrate architecture and nature. The emergence and evolution of the Renaissance garden, and Leonardo’s original contributions to landscape and garden design, are discussed in great detail by botanist William Emboden in his beautiful volume Leonardo da Vinci on Plants and Gardens.⁷⁸

A further extension of Leonardo’s organic view of buildings and his special focus on their “metabolism” is apparent in his pioneering contributions to urban design. When he witnessed the plague in Milan shortly after his arrival in the city in 1482, he realized that its devastating effects were largely due to Milan’s appalling sanitary conditions. In typical fashion, he responded with a proposal for rebuilding the city in a way that would provide decent housing for people and shelters for animals, and would allow the streets to be cleaned regularly by flushing them with water. “One needs a fast flowing river to avoid the corrupt air produced by stagnation,” Leonardo reasoned, “and this will also be useful for regularly cleansing the city when opening the sluices.”⁷⁹

Leonardo’s design of the ideal city was radical for the time. He suggested dividing the population into ten townships along the river, each with approximately thirty thousand inhabitants. In this way, he wrote, “you will disperse such great agglomeration of people, packed like a herd of goats, on each other’s backs, who fill every corner with their stench and sow the seeds of pestilence and death.”⁸⁰

In each township there would be two levels—an upper level for pedestrians and a lower level for vehicles—with stairs connecting them. The upper level would have arcaded walkways and beautiful houses with terraced gardens. At the lower level would be shops and storage areas for goods, as well as roads and canals for delivering the goods with carts and boats. In addition, Leonardo’s design included underground canals to carry away sewage and “fetid substances.”⁸¹

It is clear from Leonardo’s notes that he saw the city as a kind of living organism in which people, material goods, food, water, and waste needed to move and flow with ease for the city to remain healthy. Ludovico, unfortunately, did not implement any of Leonardo’s novel ideas. Had he done so, the history of European cities might have been quite different. As physician Sherwin Nuland points out, “Leonardo had envisioned a city based on principles of sanitation and public health that would not be appreciated for centuries.”⁸²

Two years before he died, Leonardo had another opportunity to reflect on urban design when he was asked by the king of France to draw up plans for a new capital and royal residence.⁸³ Once more, Leonardo designed a city crisscrossed with canals, to be used not only for the water supply of splendid fountains but also for irrigation, transportation, and for cleaning the city and removing waste. Again, Leonardo insisted on the importance of water circulation for the health of the urban organism. This time, work on the huge project was actually begun, but it was abandoned a few years later when an epidemic decimated the workforce.

Leonardo’s idea of urban health, based on the view of the city as a living system, was reconceived very recently, in the 1980s, when the World Health Organization initiated its Healthy Cities Project in Europe.⁸⁴ Today, the Healthy Cities movement is active in over one thousand cities around the world, most likely without participants being aware that the principles on which it is based were set forth by Leonardo da Vinci more than five centuries ago.

THE ARTIST AS MAGICIAN

One of the essential duties of the courtly artist in the Renaissance was to design the settings and scenery for court festivities—pageants and theatrical performances—with all the accessory decorations, costumes, and ephemeral architecture. Through these spectacles, the artist created for the court the images of magnificence, wealth, and power that its ruler wanted to project. The Sforza court in Milan was famous for the ostentatious affluence of its pageants, which took place at annual religious festivals as well as at a series of spectacular royal weddings. Leonardo was well aware of the importance of his role in creating dazzling spectacles for such events. He dedicated considerable time and energy to these tasks and excelled in them no less than in his other artistic pursuits. Indeed, as Arasse points out, during his lifetime “Leonardo [owed] much of his fame to his unrivaled talents as artist of the ephemeral.”⁸⁵

Theatrical performances in particular were an ideal vehicle for Leonardo to show his diversity and brilliance as a designer. For many plays at court he acted as producer, stage and costume designer, and makeup artist as well as inventor of stage machinery.⁸⁶ He carefully studied these theatrical arts and went on to create many innovations. For example, it was Leonardo who invented the first revolving stage in the history of the theater; he was also the first to raise the curtain, rather than have it fall at the start of the performance, as had been the custom.⁸⁷

For the most elaborate performances, Leonardo combined his skills of painting, costume design, musical composition, and engineering to create a complete spectacle, with moving scenery and “special effects” produced by his stage machines. To his contemporaries, these performances were awe-inspiring, bordering on magic. For example, in the production of Baldassare Taccone’s Danaë, Leonardo created dazzling illusions of Zeus’s transformation into golden rain, and of Danaë’s metamorphosis into a star. During the latter “the audience could see a star…rising up slowly towards heaven, with sounds so powerful that it seemed the palace would fall down.”⁸⁸ When he staged the play Orfeo by Angelo Poliziano, Leonardo invented a system of gearwheels and counterweights to create a mountain that would suddenly split open, revealing Pluto on his throne, rising from the depths of the underworld, accompanied by terrifying sounds and illuminated by “infernal” lights.⁸⁹ These spectacular performances firmly established Leonardo’s fame as a brilliant engineer and peerless magician of the stage.

INTERWOVEN STRANDS

The tapestries and other decorative elements designed for the courtly pageants and “masques” usually included elaborate emblems and allegories, rich in symbolism and wordplay, which served to glorify the ruling powers. Leonardo produced many of these allegorical drawings, with complex symbolic messages, many of which have been impossible for modern scholars to interpret. He also became fascinated with and used a more abstract kind of emblem featuring tangled curves in the form of knots and scrolls. These knot designs, which were very popular in the late fifteenth century, were known as fantasie dei vinci, after the reeds (vinci) used in basketry. Exploiting the fortuitous connection with his name, Leonardo used such interlaced vinci motifs as his signature designs in numerous sketches.⁹⁰

During his last two years at the Sforza court, Leonardo created the ultimate emblem for Prince Ludovico—a vast and complex fantasia dei vinci that covered the walls and vaulted ceiling of an entire room. Known as the Sala delle Asse (Room of the Wooden Boards), this is a large square room in the north tower of the Sforza Castle, in which four lunettes on each wall combine to generate an elaborate vaulting. Leonardo’s highly inventive decoration shows a grove of mulberry trees rooted in rocky subsoil, their trunks rising up to the ceiling like columns supporting the actual vaulting, their branches crisscrossing the vault in a Gothic rib structure of elegantly intertwined curves.⁹¹ The smaller twigs and leaves form a luxuriant tangled labyrinth of greenery spreading around the walls and across the ceiling. The entire composition is held together by a single endless golden ribbon winding in and out of the branches, in the complex arabesques of traditional knot designs.

The painting in the Sala delle Asse is remarkable on several levels. With his extensive knowledge of plants, Leonardo gave the branches and leaves a surprisingly realistic appearance of exuberant growth, and he gracefully and beautifully integrated these natural growth patterns into the existing architectural structure and into the geometry of the formal decoration (see Fig. 2-6). In addition, Leonardo wove multiple meanings into his leafy labyrinth that went far beyond the obligatory glorification of the Prince.⁹² The dedication of the room to Ludovico’s magnificence is obvious. Inscriptions on four prominently placed tablets praise his politics, and a shield bearing the joint coats of arms of Ludovico and his wife, Beatrice d’Este, adorns the center of the vault. The intertwining branches were meant to commemorate their union.

But there are more subtle layers of meaning to Leonardo’s design. The mulberry tree itself is rich in symbolism. The use of a stylized tree with leaves and roots was one of the Sforza emblems. The mulberry is an allusion to the prince’s well-known appellation il Moro (“the Moor”), which also means “mulberry.” The mulberry was also considered a wise and cautious tree, since it flowers slowly and ripens quickly, and hence was known as a symbol of wise government. In addition, the mulberry was connected with silk production, a major industry in Milan which Ludovico strongly encouraged. This link to industry is reinforced by the golden ribbon, which not only evokes the elegance of the Sforza court but is also a reminder of the manufacture of gold thread, another Milanese specialty.

Figure 2-6: Detail from the Sala delle Asse, 1498–99, Castello Sforzesco, Milan

At an even deeper level, Leonardo’s decoration conveys in symbolic form his conviction that human industry should integrate itself harmoniously into nature’s living forms. Indeed, it may not be too far-fetched to see the vinci decoration of the Sala delle Asse as a symbol of Leonardo’s science. The individual trunks, or columns, on which it rests, might be seen as the treatises he planned to write on various subjects, grounded in the soil of traditional knowledge, but intended to break through the rocks of the Aristotelian worldview and take human knowledge to new heights. As the contents of each treatise unfolded, they would interlink with each other to form a harmonious whole. The similarities of patterns and processes that interconnect different facets of nature provide the golden thread that integrates the multiple branches of Leonardo’s science into a unified vision of the world.

One hundred years after Leonardo, the French philosopher René Descartes compared science (or “natural philosophy,” as it was then called) to a tree. “The roots are metaphysics,” he wrote, “the trunk is physics, and the branches are all the other sciences.”⁹³ In Descartes’ metaphor, physics, itself grounded in metaphysics, was the single foundation of all the sciences, the discipline that provides the most fundamental description of reality. Leonardo’s science, by contrast, cannot be reduced to a single foundation, as we have seen. Its strength does not derive from a single trunk, but from the complex interconnectedness of the branches of many trees. For Leonardo, recognizing the numerous patterns of relationships in nature was the hallmark of a universal science. Today, we, too, sense a greater need for such universal, or systemic, knowledge, which is one of the reasons why Leonardo’s unified vision of the world is so relevant to our time.

In the following chapters I shall follow Leonardo’s golden ribbon along various branches of his science of living forms. But before beginning that journey, it is important to know more about when and where those branches grew and foliated in his own life.